1. Field of the Invention
The present invention relates to a method for sealing packages, as well as an apparatus for the same. More particularly, the present invention provides a sealing apparatus and method which utilize a plurality of sealing rigs in order to increase package flow rates.
2. Description of Related Art
Most products are containerized in outer packages prior to shipment to consumers and other end users. The packaging step is usually an integral part of the production process, and can be a limiting factor in maximizing throughput. Thus, it is usually advantageous to optimize the speed and efficiency of this packaging step as much as possible, without adversely affecting the product quality.
Typically, products are inserted into a package comprising a bag, a box or other appropriately-sized container, and this container is then sealed in order to isolate the product from the ambient. These containers may be sealed by any of a number of means, including various types of adhesives and/or heat sealing. Heat sealing is accomplished by welding one portion of the container to another (e.g., heat welding opposing edges of a plastic bag to one another). This sealing step, however, is often not conducive to continuous manufacturing processes, since the sealing step requires the application of pressure and/or heat for a minimum period of time in order to effectuate proper sealing. This sealing time is significant, since the containers must either be paused at the sealing device for a minimum period of time, or the sealing device itself must be movable with the stream of packages. The former alternative can interrupt product flow within the manufacturing process, while the latter can be expensive to implement.
By way of example, consumer products such as diapers are typically packaged in an outer container comprising a flexible film (such as polyethylene or polypropylene) bag. The diapers are inserted through the open end of the bag, opposing sides of the open end portion of the bag are tucked inwardly, and the opposing top and bottom flaps at the open end of the bag are then affixed to one another in order to seal the bag of diapers. Typically, the opposing flaps are fused to one another by the application of heat, with or without the use of additional adhesives such as glues and the like. A pair of sealing jaws are closed about the opposing flaps in order to fuse the flaps to one another. These sealing jaws generally provide sufficient heat and pressure to fuse or weld the opposing film flaps to one another. The sealing jaws must be closed about the flaps for a minimum engagement time, however, to ensure sufficient energy transfer for a fusion of the materials. Therefore, in order to achieve higher sealing rates, and therefore a greater product throughput, product streams are often split into multiple lanes for delivery of the bagged products to multiple sealing devices.
Splitting of the product stream into multiple lanes is problematic in that the straight-line path from the bag loading station to the sealing device is no longer maintained, and control of the end flaps may be lost if additional control mechanisms are not employed. Taking additional steps to ensure that the product within the bags or containers will not be dislodged or for maintaining control of the end flaps, however, generally entails added expense, and splitting of the product stream into multiple lanes for package sealing requires additional floor space within the manufacturing facility. Alternatively, more expensive packaging materials can be employed wherein these materials have fusion properties which require shorter engagement times for the sealing jaws.
Thus, there is a need for an improved apparatus and method for sealing a stream of packages wherein multiple infeed lanes to the sealing devices are not needed, and conventional packaging materials may be employed.